Coral reef degradation in the Indian Ocean. Status reports and project presentation 2000. Item Type Report Publisher CORDIO & SAREC, Stockholm University Download date 30/09/2021 18:19:16 Link to Item http://hdl.handle.net/1834/309 South Asia - Summary DAN WILHELMSSON CORDIO – South Asia, c/o SACEP, Colombo, Sri Lanka This summary is a synthesis of reports from Pet-Soede Early reports from the Andaman and Nicobar Is- et.al., Zahir and Rajasuriya & Karunarathna presented lands indicated 80% of all corals bleached. However, the in this volume. All numbers in the text refer to the extent of post bleaching mortality has not been estab- project list below. lished. The reefs of South Asia, including Maldives, Sri Results of a study of the socio-economic importance Lanka and India were severely affected by the bleaching of reef fisheries in India (3), suggested that, despite the event of 1998, with subsequent mortality of ranging be- relative unimportance of India’s reef fisheries at present, tween 50% and 100%. Surveys of these reefs conducted the increasing demands for food caused by burgeoning during 1999 and at the beginning of 2000 recorded some coastal populations and overexploitation of coastal shelf coral recruitment, but many areas still show no signs of areas will increase the pressure on India’s coral reefs to recovery. provide food and economic well-being to these coastal and island populations. INDIA The reefs of the Gulf of Mannar were severely affected MALDIVES by mortality of coral during 1998. Post bleaching sur- Results of monitoring of the reef tops conducted during veys on the coral reefs of the 21 islands in the Gulf show 1999 show that the cover of live coral has not increased the mean cover of coral is approximately 26%. However, since the post bleaching surveys conducted in 1998 and there is considerable variation between reefs with the remains at approximately 2%. At present, the cover of cover of live coral ranging between 0% and 74%. In ad- live coral is 20 times lower than that recorded before the dition to reef-building corals, sea anemones and octocor- bleaching event. However, re-colonisation of fast grow- als (soft corals) also bleached as a result of the increased ing branching corals has been recorded, indicating that sea temperatures that prevailed during 1998. Subse- reef recovery processes are underway. Furthermore, on quently, a decrease in biodiversity of these reefs has been some reefs coralline algae are abundant providing po- reported. Furthermore, extensive beach erosion on some tential areas for coral recruitment. Nevertheless, despite islands was reported. these reasons for hope, it is clear that the reefs of Mal- Initial assessments of recovery processes in Lack- dives were seriously affected by bleaching and subse- shadweep Islands during 1999 indicate the cover of live quent mortality of coral and will require many years to coral has increased to 15% to 20 % compared with the recover. 5% to 10% reported immediately after the bleaching In addition to biophysical monitoring of the reefs, event. Infrastructure and capacity needed for continua- studies were conducted to determine the spatial and tion of the work are being created (1). temporal patterns of coral recruitment in Maldives (4). – 51 – The distribution of coral reefs in the South Asia region of the Indian Ocean. More detailed maps are provided illustrating areas of particular interest. Initial results suggest that there is potential for the Considering the importance of reef related tourism degraded reefs of Maldives to recover through the in- in Maldives, a survey was conducted to evaluate the po- flux of coral planulae from surviving colonies elsewhere. tential economic impacts on the national economy of Also, the degree of erosion and changes in the topo- Maldives from declines in tourism resulting from graphic complexity of these reefs are being assessed fol- bleaching induced degradation of coral reefs (6). Con- lowing the extensive coral mortality in Maldives (5). sidering the importance of reef related tourism in Mal- The CORDIO program has also trained staff at the dives, a survey was conducted to evaluate the potential Marine Research Centre in Maldives responsible for economic impacts in the Maldives from tourism due to conducting the CORDIO activities. The training fo- degradation of coral reefs (6). Results suggest that, al- cussed on general survey methods including taxonomic though not severely, the tourism industry was adversely identification of major reef biota and on specific proto- affected by the coral mortality in the Maldives (see cols for conducting assessments of recruitment and ero- Westmacott et al., this volume). sion of reefs. – 52 – SRI LANKA mental fisheries and reef related tourism (8). Building Most shallow coral reef habitats in Sri Lanka were se- on these results, another project is planned to investigate verely damaged as a result of coral bleaching in 1998. the prospects of providing alternative livelihoods for de- Surveys conducted between June 1998 and January 2000 pendants on coral reefs (9). (7) revealed that many of the dominant forms of reef In addition, CORDIO, with assistance from Nation- building corals in the shallow coral habitats have been al Aquatic Resources Research & Development Agency destroyed. Invasive organisms such as tunicates, coralli- (NARA), has begun training students of Eastern Uni- morpharians and algae now dominate the dead coral versity in the basic techniques of coral reef monitoring, reefs. Furthermore, the dead coral patches were rapidly with the aim of developing the local capacity to under- inundated by sediment thus preventing re-colonization take such monitoring. The training includes coral and of coral larvae. Also, in every area surveyed thus far, ex- fish taxonomy, LIT (Line Intercept Technique) and cept Trincomalee in the northeast, the hydrocoral, data analysis. Millepora spp., which was once common, appears to be completely absent. However, despite the destruction of PROJECT LIST corals in shallow water (< 8 m), corals growing in deep- India er waters (> 10 m) have recovered from bleaching al- Country co-ordinator: M.V.M. Wafar most completely providing a source for new recruits and Institute: National Institute of Oceanography reef recovery. 1. Recovery and monitoring of the reefs. Recovery of bleached corals in shallow reef habitats 2. Assessment of the effects of coral mortality on reef has been extremely low and has been hindered by fur- communities. ther damage to the reef structures by uncontrolled and 3. Socio-economic effects on local populations and destructive human activities. Even the marine protected tourism. areas in Sri Lanka are largely unmanaged and increas- Maldives ing human activities within these protected areas con- Country co-ordinator: Hussein Zahir tinue to degrade their condition. Considering the Institute: Marine Research Centre present condition of the reefs and the inevitability of fu- 1. Reef recovery processes: Evaluation of succession ture anthropogenic impacts, the prospects for reef recov- and coral recruitment in the Maldives ery are poor. 2. Assessing bioerosion and its effects on reef structure The impact on fishes by the loss of live hard corals is following a bleaching event in the Maldives. clearly visible in the decreased abundance of several spe- 3. The economics of coral reef deterioration with speci- cies of fish that depend on live corals for food (e.g. Cha- al reference to bleaching. etodonts). However, it is less obvious in fish populations in deeper water that are less dependent on live corals for Sri Lanka their survival. Nevertheless, it is expected that the re- Country co-ordinator: Arjan Rajasuriya duction in cover of live hard coral will directly affect the Institute: National Aquatic Resources Research & De- fishery potential of reefs through habitat degradation velopment Agency and loss thus, having an adverse impact on the income 1. Impacts of coral bleaching on reef communities. of coastal communities. 2. Monitoring and assessment of socio-economic aspects At present, a study is being conducted to determine of coral bleaching and degradation in Sri Lanka. the socio-economic impacts of degradation of the coral 3. Develop alternative livelihoods for people dependent reefs of Sri Lanka, focusing on the demersal and orna- on coral reef resources. – 53 – Post-bleaching status of the coral reefs of Sri Lanka ARJAN RAJASURIYA and CHAMINDA KARUNARATHNA National Aquatic Resources Research and Development Agency, Colombo, Sri Lanka ABSTRACT reef habitats at selected locations around Sri Lanka two Most shallow coral reef habitats in Sri Lanka were se- years after the bleaching event of 1998 and discusses the verely damaged as a result of coral bleaching in 1998. implications of their lack of management in the context Surveys conducted between June 1998 and January 2000 of reef recovery. revealed that many of the dominant forms of reef build- ing corals such as Acropora spp., Pocillopora spp. and Echinopora lamellosa in shallow habitats have been de- INTRODUCTION stroyed. Montipora aequituberculata and Porites rus were In Sri Lanka three major types of reef habitats have only marginally affected. Overall, recovery of bleached been classified based on the dominant forms of sub- corals among shallow reef habitats has been poor. Inva- strate. These are coral, sandstone and rock habitats sive organisms such as tunicates, corallimorpharians and (Swan, 1983; Rajasuriya & De Silva, 1988; Rajasuriya et algae